Open Access Atlas of Otolaryngology, Head & Neck Operative Surgery

OPEN ACCESS ATLAS OF OTOLARYNGOLOGY, HEAD & NECK OPERATIVE SURGERY

PARATHYROIDECTOMY Eugenio Panieri & Johan Fagan

Parathyroidectomy is indicated for primary avoid injury to important local structures, hyperparathyroidism and for secondary particularly the recurrent laryngeal nerve hyperparathyroidism refractory to medical (RLN). treatment (Figures 1, 2). There are typically four parathyroid glands; supernumerary glands and <4 glands do occur. The parathyroids are generally located symmetrically in the neck in close proximity to the thyroid gland (Figure 3).

Ext Carotid artery

Inf constrictor RLN Cricothyroid

Parathyroids Figure 1: Typical parathyroid adenoma Sup thyroid art

Inf thyroid art

RLNs

Oesophagus

Thyrocervical trunk

Figure 3: Posterior view of the thyroid gland demonstrating parathyroids, RLNs and superior and inferior thyroid arteries

Their characteristic golden-tan colour varies from yellow to reddish brown. Their colour permits for them to be distinguished Figure 2: Giant sized adenoma from the pale-yellow lymph nodes, thymus, mediastinal fat, and the dark-red Surgical Anatomy thyroid parenchyma. They have a diameter of about 3-8 mm and are usually oval- A detailed knowledge of parathyroid ana- shaped, but may also be tear-shaped, drop- tomy is essential to perform parathyroidec- like, spherical, elongated, rod-like or tomy safely and effectively. Particular at- flattened. tention needs to be paid to identifying ectopic or unusually located glands and to The superior parathyroid glands originate from the 4th pharyngeal pouch and adhere to the posterior surface of the caudally mi- The inferior parathyroid glands arise from grating thyroid. They have a much shorter the dorsal wings of the 3rd pharyngeal distance to migrate than the inferior para- pouches. They join the thymus as it migra- thyroid glands; this would account for their tes caudally and medially to its final posi- more predictable location. They are em- tion in the mediastinum. Ectopic inferior bryologically and anatomically closely parathyroid glands can be found anywhere related to the Tubercle of Zuckerkandl and along this large area of descent from the are usually found posteriorly at the level of proximal neck down to the superior border the upper two-thirds of the thyroid about of the pericardium. Their commonest loca- 1cm above the crossing point of the RLN tion is on the anterior or the posterolateral and inferior thyroid artery (ITA) (Figure surfaces of the lower pole of the thyroid, 4). between the lower pole of thyroid and thyroid isthmus (42%, Wang et al); or within the thyrothymic ligament in the lower neck in proximity to the thymus (39%). Other locations include lateral to the thyroid, TZ within the carotid sheath (15%), or within Sup parathyroid mediastinal thymic tissue and pericardium (2%). (Figure 5) RLN The inferior parathyroids are usually found in a plane more ventral to that of the superior glands. If the RLN’s course is viewed in a coronal plane, then the superior para- Figure 4: Tubercle of Zuckerkandl (TZ) thyroid glands are located deep (dorsal) and its relationship to the superior para- and the inferior parathyroid superficial thyroid gland and RLN (ventral) to the plane of the nerve (Figures 6, 7). Ectopic superior parathyroids are uncom- mon (1%) and may be found in the posterior neck, retropharyngeal and retroesophageal spaces and intrathyroidally (Figure 5).

Thyroid cartilage

Superior parathyroid

Oesophagus Figure 6: The superior parathyroid gland Inferior parathyroid lies deep (dorsal) and the inferior para- Thymus thyroid superficial (ventral) to a coronal plane along course of RLN

Figure 5: Ectopic parathyroids in retropharyngeal space and mediastinum 2 to the parathyroids, thyroid, upper oesophagus and trachea. Its branches communi- cate with the superior thyroid artery (STA) and with the blood supply of the contra- Inferior PT lateral thyroid lobe via the thyroid isthmus.

Superior PT The Recurrent Laryngeal Nerve (RLN) is a key structure in any exploration of the RLN central neck. Identification and preserva- tion of the RLN during thyroid and para- Figure 7: The superior and inferior parathyroid surgery is essential to minimise thyroids relative to a coronal plane along morbidity. The RLN innervates all the the course of the RLN intrinsic muscles of the larynx except the cricothyroid muscle (SLN) and provides The inferior thyroid artery (ITA) is a sensory innervation to the larynx. Even branch of the thyrocervical trunk, which in minor neuropraxia may cause dysphonia; turn arises from the subclavian artery irreversible injury confers permanent hoar- (Figures 3, 5). It is the predominant vas- seness. The incidence of RLN injury cular supply to both the upper and lower during thyroidectomy is 0-28% and is the parathyroids (Figures 3, 8). Consequently, most common reason for medicolegal division of the main trunk of the ITA claims following thyroidectomy; the inci- during thyroidectomy is discouraged as it dence of injury during parathyroidectomy places both parathyroids at risk of ischae- is much lower. mic injury. The RLNs originate from the Xn. After circling around the subclavian artery (right) and aortic arch (left) the RLNs course superiorly and medially toward the tracheoesophageal groove (Figures 9, 10). STA The right RLN enters the root of the neck from a more lateral direction and its course is less predictable than that of the left. The RLNs enter the larynx deep to the inferior ITA constrictor muscles and posterior to the Thyrocervical cricothyroid joint. Subclavian The RLN may be non-recurrent in approximately 0.6% of patients i.e. it does not pass around the subclavian artery but Figure 8: Superior thyroid artery (STA), branches from the Xn higher up in the subclavian artery, thyrocervical trunk and neck, passing directly to the larynx close to inferior thyroid artery (ITA) the superior thyroid vessels (Figure 10). This aberration almost always occurs on The ITA courses superiorly along the sur- the right side and is associated with a face of the anterior scalene muscle before retroesophageal subclavian artery. turning medially behind the carotid sheath from where it reaches the inferior pole of Knowledge of the anatomical relationships the thyroid gland. It provides blood supply of the RLN to the tracheoesophageal

3 Figure 11 the RLN is seen to pass anterior to the artery.

Figure 11: RLN passing over the inferior Figure 9: Posterior view of the course of thyroid artery (right neck, thyroid reflected the RLNs medially)

The majority of RLNs are located within 3mm of Berry’s ligament; rarely the nerve is embedded in it, and more commonly lies lateral to it.

Classically, the RLN is identified intra- operatively in Simon’s triangle, which is formed by the common carotid artery laterally, the oesophagus medially and the ITA Xns superiorly (Figure 12). RLNs

Subclavian arteries

Aortic arch Trachea

RLN

ITA

Figure 10: Typical anatomical course of Carotid RLNs (non-recurrent RLN in red) groove, ligament of Berry, and ITA is Figure 12: RLN crossing Simon’s triangle essential. The course of the RLN with re- formed by trachea, ITA and common caro- spect to the ITA is quite variable. Most tid artery commonly it crosses behind the branches of the artery, more predictably so on the The Tubercle of Zukerkandl may also be left. However, the nerve may pass deep to, used as an anatomical landmark to identify superficial to, or between the terminal the nerve (Figure 4). The RLN generally branches of the ITA. Up to twenty anato- courses between this structure and the mical variations have been described. In trachea. However, this relationship can 4 vary with enlargement of the tuberculum sing between the branches of the STA as it thereby placing the nerve at risk during enters the superior pole of the thyroid surgical exploration. gland; in such cases it is particularly vulne- rable to injury. Superior Laryngeal Nerve (SLN) SLN Ext branch The SLN is a branch of the Xn and has both an external and internal branch (Figu- STA res 13, 14). The internal branch is situated Thyroid above and outside the normal field of dissection; it is sensory and enters the larynx STVs through the thyrohyoid membrane.

The external branch innervates the cricothyroid muscle, a tensor of the vocal cord. Injury to the SLN causes hoarseness, de- creased pitch and/or volume, and voice Figure 14: Note close proximity of external fatigue. These voice changes are more sub- branch of SLN to STA and thyroid vein and tle than those relating to RLN injury are to superior pole of thyroid gland frequently underestimated and not reported. The external branch is at risk because Types of parathyroidectomy of its close proximity to the STA (Figures 13, 14). Understanding its relationship to Focused parathyroidectomy: This is the the upper pole of the thyroid and the STA usual procedure for a well-localised is crucial to preserving its integrity. solitary adenoma. The offending gland is removed through a limited incision with direct exposure of the previously imaged XIIn parathyroid adenoma.

SLN (internal) Bilateral neck exploration: In cases of unsuccessful preoperative localisation the SLN (external) surgeon explores the necks fully, identifies all four parathyroid glands and removes STA the adenoma.

Sup pole Subtotal parathyroidectomy: This is thyroid indicated with parathyroid hyperplasia when all the glands have the capacity for increased parathyroid hormone (PTH) pro- Figure 13: Anatomical relations of inter- duction. This occurs in secondary and nal and external branches of right SLN to tertiary hyperparathyroidism and in the STA and to superior pole of thyroid unusual situation of primary hyperparathyroidism due to multiple gland hyper- The usual configuration is that the nerve is plasia. The three largest glands are remov- located behind the STA, proximal to its ed and a small remnant of the most entry into the superior pole of the thyroid. normal-looking gland is either left in situ The relationship of the nerve to the supe- or transplanted to an ectopic site, typically rior pole and STA is however extremely the forearm. variable. Variations include the nerve pas-

5 Total parathyroidectomy: All parathyroid respectively) is the best approach for pre- tissue is removed. This may be done as a operative localisation with single gland salvage procedure in cases of recurrent disease. Unfortunately, these favourable secondary hyperparathyroidism. results do not apply to all patients with parathyroid disease. It is important to note Preoperative evaluation: Primary that failed localisation does not exclude hyperparathyroidism primary hyperparathyroidism and is not a contraindication for surgical exploration. Endocrine diagnosis: The diagnosis of primary hyperparathyroidism hinges on Ultrasonography (US): The thyroid and identifying an inappropriately raised PTH surrounding structures can be evaluated assay in the presence of elevated serum with US. It has gained popularity due to calcium. It is not unusual for hypercal- the ease of the technique; many endocrine caemia symptoms of primary hyperpara- surgeons have the expertise to evaluate the thyroidism to be non-specific and vague; neck in their own offices. Resolution has hence it is often underestimated. Typical improved with newer generation equip- presentations include recurrent renal cal- ment. The weaknesses of US are similar to culi, progressive bone density loss, patho- 99mTc-sestamibi i.e. deep superior glands, logical fractures, ill-defined musculoskele- ectopic glands and too-small glands are tal complaints, neurocognitive impairment, difficult to localise, and the mediastinum is and unexplained abdominal pain; or it may inaccessible. present as a hypercalcaemic crisis. While the diagnosis of primary hyperparathy- CT and MRI: CT and MRI are not roidism is not difficult to make for sur- indicated as first line investigations, but geons well versed in endocrine disorders, may be useful to evaluate parathyroid ade- the occasional parathyroid surgeon is well nomas with non-localising imaging studies advised to consult an endocrinologist prior or previously operated necks. to proceeding with surgery. Preoperative evaluation: Secondary SestaMIBI scan: This is a nuclear medici- hyperparathyroidism ne imaging technique with the highest sen- sitivity and specificity for identification of This diagnosis requires identification of an primary hyperparathyroid adenomas and is inappropriately raised PTH assay in the the authors’ investigation of choice. The presence of an abnormally elevated serum use of Technetium99m (Tc99m) sestamibi for phosphate-to-calcium ratio. The serum parathyroid imaging has led to a steady calcium typically falls within the normal refinement of imaging. The accuracy is range. Secondary hyperparathyroidism is determined by the scanning technique almost always diagnosed in patients with employed; the dual-isotope (I123/ Tc99m chronic renal failure. Rarer causes include sestamibi) scan provides better accuracy osteomalacia, rickets, and malabsorption. than the simpler sestamibi washout meth- Secondary hyperparathyroidism contribu- od. The pathological parathyroid can be tes significantly to renal osteodystrophy localised preoperatively with great confi- and is associated with accelerated athero- dence allowing for a quicker and more sclerosis, ectopic soft tissue calcification focused neck exploration. Recent data and skin ulcers in calciphylaxis. It contri- would suggest that the combination CT- butes to a general feeling of malaise and 99mTc-sestamibi-SPECT (reported sensiti- musculoskeletal pain seen in chronic renal vity and specificity of up to 88% and 99% failure, and chronic pruritus. Close colla-

6 boration with a renal physician is essential Anaesthesia, positioning and draping to determine the best time for surgical intervention. • General anaesthesia with endotracheal intubation; local anaesthesia is possible Preoperative consent with confident preoperative localisation Scar: The incision is typically well-hidden • Prophylactic antibiotics are not requi- within a natural skin crease of the neck but red tends to descend with ageing. • The neck slightly hyperextended by placing a bolster between the scapulae Airway obstruction/wound haematoma: • The head is stabilised on a head ring <1% of parathyroidectomy patients are • The table is tilted to 30º anti-Tren- stridulous postoperatively due to a haema- delenberg to reduce venous engorge- toma, oedema of the airway or injury to the ment RLNs. • The head is free draped to allow turning of the head Voice change: It is essential that the patient has a clear understanding of the risks Surgical technique relating to voice quality prior to surgery. While less common than with thyroidecto- Because identification of parathyroid my, permanent RLN dysfunction does glands is reliant on subtle shades of occur. The risk is highest with repeat sur- colour and consistency, the recognition of gery or with parathyroid carcinoma. parathyroid tissue can be impossible in a bloodied surgical field; meticulous hae- Hypocalcaemia: Transient hypocalcaemia mostasis is therefore critical. Whilst para- occurs in approximately 20% of patients thyroidectomy is often simple and quick, it following successful removal of adenomas. is not a procedure that can be rushed and Paradoxically the higher the levels of should be booked early on an operating list calcium and PTH preoperatively, the great- to avoid undue pressure in terms of availa- er the postoperative drop in calcium. Most ble operating time. The surgeon must be patients can be managed on oral calcium calm, unrushed and have a good assistant. supplements until the remaining parathyroid glands re-equilibrate. Hypocalcaemia Skin incision: A curvilinear incision is occurs in all cases of secondary hyper- placed in a skin crease approximately two parathyroidism and requires proactive finger breadths above the sternal notch be- management with large doses of oral cal- tween the medial borders of the sterno- cium supplements and Vitamin D1-α. Per- cleidomastoid muscles (Figure 15). It is sistent symptoms require intravenous cal- seldom necessary to make the incision lon- cium supplementation. ger than 4-5cm. Well-localized glands can be resected via a smaller incision. Placing Failed exploration: Some cases of hyper- the incision too low causes an unsightly parathyroidism cannot be corrected surgi- low scar over the heads of the clavicles cally due to unusual pathology or failure to when the extended neck is returned to its remove the pathological ectopic para- normal position. thyroids; the risk of failed exploration is approximately 5%. Subplatysmal flaps: Subcutaneous fat and platysma are divided, and a subplatysmal dissection plane is developed superiorly

7 (platysma is often absent in the midline) Surgical Approaches remaining superficial to the anterior jugular veins, up to the level of the thyroid 1. Lateral approach involves dissecting cartilage above, and the sternal notch along the medial border of the sterno- below (Figure 16). cleidomastoid muscle to the carotid sheath, and then medial to the sheath The skin flaps are secured with a fixed up to the thyroid region. This is retractor (Figure 17). employed in cases of confident preoperative localisation. 2. Anterior approach involves medial mobilisation of the thyroid gland. This is used in cases of possible bilateral neck exploration. It is favoured by the author and is described in more detail below.

Separating strap muscles and exposing Figure 15: Curvilinear skin incision two the anterior surface of thyroid: The fascia finger breadths above the sternal notch between the sternohyoid and sternothyroid muscles is divided in the midline with diathermy or scissors (Figure 18). This is an avascular plane, though care must be taken not to injure small veins occasionally crossing between the anterior jugular veins, particularly inferiorly. The infrahyoid (sternohyoid, sternothyroid and omohyoid) strap muscles are retracted laterally with a right-angled retractor. In difficult cases the strap muscles may be divided to improve access. Figure 16: Subplatysmal flaps elevated

Figure 18: Fascia between sternohyoid Figure 17: Subplatysmal skin flaps held and sternothyroid muscles divided to with Jowell’s retractor. Note anterior expose thyroid gland jugular veins (AJVs)

8 It is usual at this stage for the surgeon to move to the side of the table opposite to the parathyroid to be resected.

Delivery of thyroid towards midline: The infrahyoid (sternohyoid, sternothyroid and omohyoid) strap muscles are retracted laterally with a right-angled retractor. The thyroid gland is delivered medially by applying gentle digital traction to the gland (Figure 19).

Figure 20: Dividing the middle thyroid vein

The superior parathyroid gland is normally located in a posterior position at the level of the upper two-thirds of the thyroid and is closely related to the Tubercle of Zuck- erkandl; it is about 1cm above the crossing point of the RLN and ITA. If the RLN’s course is viewed in a coronal plane, then Figure 19: Medial rotation of (R) thyroid the superior parathyroid gland lies deep lobe exposes the middle thyroid vein (dorsal) to the plane of the nerve (Figures 4, 6, 7). It has a characteristic rich orange/ Division of middle thyroid vein(s): The yellow colour (Figures 21, 22). The (occa- vein is the first key vascular structure to be sional) para-thyroid surgeon may find the encountered and is tightly stretched by me- parathyroids difficult to identify especially dial traction on the gland (Figure 19). if there has been bleeding in the surgical Dividing the vein facilitates additional field, so care must be taken to ensure mobilisation of the gland and permits meticulous haemostasis. delivery of the bulk of the thyroid lobe into the wound (Figure 20). Although dividing it is not always essential, it is better to do so than to risk tearing it. TZ If the surgeon is confident about preoperative localisation then dissection is next Sup parathyroid directed at the parathyroid adenoma. Crossing point of RLN & STA Identifying superior parathyroid: Full mobilisation and anterior delivery of the upper pole of the thyroid brings the region of the Figure 21: Position of superior para- superior parathyroid gland into direct view. thyroid relative to Tubercle of Zuckerkandl (TZ), RLN and STA

9 delicately grasping its capsule until the vascular pedicle is identified. This is then be ligated with a 3/0 tie.

Inferior PT

Superior PT

RLN

Figure 22: Superior and inferior parathyroids (PT)

The gland must remain in situ with blood supply intact. This is best achieved by carefully dissecting it off the posterior aspect of the thyroid gland and using short Figure 23: Right superior parathyroid bursts of bipolar cautery to control bleed- adenoma being removed ing. If the gland still cannot be identified, it is prudent to divide the STA and com- pletely mobilise the upper pole of the thyroid. This will almost certainly bring the superior parathyroid into view.

Identification of inferior parathyroid: The inferior gland is initially looked for at the inferior aspect of the lower pole of the thyroid or within the thyrothymic ligament. If the RLN’s course is viewed in a coronal plane then the inferior parathyroid is superficial (ventral) to the plane of the Figure 24: Right inferior parathyroid nerve (Figures 6, 7, 21, 22). Its location is adenoma more varied than with the superior gland, but if it is at its expected location then it is Confirming successful removal: After generally simpler to identify. The inferior identifying the parathyroid glands, it is es- parathyroids are most commonly located sential to distinguish between normal and between the lower pole of the thyroid and pathological glands. Simple rules of thumb thyroid isthmus, most commonly on the are that increased size correlates with anterior or posterolateral surfaces of the pathology, and that marked elevations of lower pole of the thyroid (42%, Wang et calcium and PTH levels are usually caused al), or may be located in the lower neck in by larger adenomas. Adenomas are typical- proximity to the thymus (39%). Preserving ly more rounded than normal parathyroid it in situ avoids damaging the ITA blood glands and have a darker, fleshy paren- supply. chymal appearance, sometimes described as similar to a “rat’s heart”. They are typi- Removal of adenoma: (Figures 23, 24) cally 1-2cm in diameter and are signifi- Once the abnormal parathyroid has been cantly heavier than normal glands (Figure identified, it is removed. Parathyroid tissue 25). Occasionally small adenomas (<1cm) can autotransplant if fragmented, so great and very large ones (up to 8cm) are found care is taken to deliver an intact gland by (Figure 1). 10 dependent. A commonly used criterion for curative resection is a 50% drop in ioPTH levels (compared with baseline) at 5, 10, and 15min following resection; a persistently elevated ioPTH in- dicates inadequate cure and necessi- tates further exploration. It requires access to a rapid ioPTH assay machine which should ideally be located in/ close to the operating room to avoid unnecessary delays.

The missing gland: Most parathyroid operations are simple, quick and rewarding for both surgeon and patient. However, on occasion parathyroid glands may be Figure 25: Typical parathyroid adenomas infuriatingly difficult to identify and tests

the skill and patience of even the most The occasional parathyroid surgeon is well experienced endocrine surgeon. Surgery is advised to confirm that abnormal parathy- likely to be more complex in the following roid tissue has been removed as it is easy situations and the occasional parathyroid to mistake fat, lymph gland, thymus, a surgeon should consider referring such superficial thyroid nodule, or normal para- cases to an expert: thyroid for an adenoma, particularly if the dissection has been difficult. This can be • Normocalcaemic hyperparathyroidism done in two ways: • Failed/discordant preoperative localisation imaging 1. Routine frozen section histology. Dis- • Concomitant, large multinodular thy- tinguishing between parathyroid and roid disease other tissue is quick and simple to do; • Failed previous exploration but it is not good for differentiating • Family history suggestive of MEN syn- between normal parathyroid, hyper- drome plastic parathyroid or adenoma. If exploration fails to reveal convincing 2. Rapid intraoperative PTH assays evidence of a parathyroid adenoma, then (ioPTH) allow endocrine surgeons to two likely scenarios apply: record an immediate drop of PTH level • All 4 parathyroids have been found, as an accurate marker of surgical cure but none looks convincingly pathologi- of hyperparathyroidism because of the cal: it is probable that the patient has short half-life of PTH. A large-bore four-gland hyperplasia, and a subtotal peripheral IV line is used to draw parathyroidectomy is indicated. Fro- blood for ioPTH levels both prior to zen section is invaluable to confirm (baseline) and following excision of that removed tissue is truly parathyroid the adenoma. From the time the blood tissue is drawn, the assay takes approximately • If 3 normal-looking glands have been 15min. It is essential to measure PTH identified it is probable that the missing levels as soon as possible to the time of gland is the adenoma and a more resection of the adenoma as PTH meas- exhaustive search is required urements are labile and likely position-

11 A missing superior parathyroid gland is • Approximate the strap muscles in the almost always located where it is meant to midline along 70% of their lengths be i.e. in its normal position at the level of • Close the platysma layer with interrup- the upper two-thirds of the thyroid, in a ted absorbable 3/0 sutures posterior position, about 1 cm above the • Skin closure is achieved with a subcuti- point where the RLN crosses the ITA. The cular absorbable monofilament suture surgeon needs to further mobilise the upper • A light dressing is applied pole of the thyroid anteriorly. The parathyroid may be covered by a fine layer of Postoperative care thyroid capsule; dissecting onto the thyroid parenchyma itself may release it and bring • Keeping thorough records is invaluable it into view. Should it still not be visible in cases of recurrent hyperparathyroid- one then needs to transect the STA to fully ism. Therefore, keep meticulous and mobilize the upper pole. If it still cannot be detailed notes about the extent of the located, then one may be dealing with the exploration noting which normal para- rare situation of ectopic retro-oesophageal thyroid glands were seen, precisely and retropharyngeal locations and these where they were located and what regions need to be explored. tissue was removed • The intravenous line is removed, and a A missing inferior parathyroid gland normal diet is taken as tolerated poses more of a challenge as the anato- • Following successful focussed para- mical variations are greatest. The follow- thyroidectomy the patient may be dis- ing areas need to be systematically explo- charged the same day red: • More complex cases are monitored

• Lower pole of thyroid. overnight for bleeding or airway • Thyrothymic ligament obstruction • Simon’s triangle, just below the ITA • Serum PTH levels are routinely mea- • Thymectomy by applying traction to sured 24hrs postoperatively. A return the thyrothymic ligament to normal PTH levels confirms a • Lateral cervical space, behind the caro- successful operation. A hypocalcae- tid sheath towards the posterior media- mic trough occurs 2-5days post- stinum operatively. Calcium and Vitamin • Carotid sheath D1α are commenced pre-emptively if • Retro-oesophageal space the PTH reading is low

If this still fails to identify pathological Specific Scenarios glands it is then reasonable to abandon the procedure and to consider secondary Secondary hyperparathyroidism: Up to exploration after more exhaustive imaging 90% of patients meeting criteria for hae- 6-12 months later. modialysis have secondary hyperparathyroidism. Surgery is indicated for: Wound closure • Calciphylaxis • Patient preference • Irrigate the wound • Medical observation not possible • Do a Valsalva manoeuvre and check • Failure of maximum medical therapy for bleeding with persistent hypercalcaemia, hyper- • Wound drainage is not routinely re- calcuria, PTH >800pg/mL and hyper- quired phosphataemia 12 • Osteoporosis considered, most missed parathyroid • Progressive symptoms e.g. pruritus, glands are located within the cervical re- pathologic bone fractures, ectopic soft gion. Repeat neck exploration for persis- tissue calcification, severe vascular cal- tent or recurrent disease can be very diffi- cification, and bone pain cult as the normal tissue planes are scarred and it is associated with higher rates of Three different surgical procedures invol- injury to the RLN and permanent hypo- ving bilateral neck exploration are em- parathyroidism. The lateral or ‘‘back- ployed for patients with secondary hyper- door’’ approach (dissection between the parathyroidism who fulfil criteria for anterior border of the sternocleidomastoid surgery. Each operation has its proponents muscle and posterior border of the strap and an institutional history. There is no muscles) may be useful as it provides convincing evidence of superiority of any direct access to the posterior surface of the one approach: thyroid gland without encountering scar • Subtotal parathyroidectomy i.e. remov- tissue from previous surgery done through ing 3½ glands and leaving a ½-gland the conventional anterior approach. remnant in situ (author’s preference) • Total parathyroidectomy (four-gland Radioguided parathyroidectomy: This resection) with autotransplantation technique may be helpful with complex • Total parathyroidectomy (four-gland repeat surgery, but the author does not use resection) without autotransplantation it for routine parathyroidectomy due to cost and logistic constraints. It is similar to Repeat surgery for failed exploration: other radioguided techniques such as Such cases should be managed by surgeons sentinel lymph node biopsy. A parathy- well-versed in the subtleties of parathyroid roid-specific radiotracer such as Tc99m- surgery. The following issues need to be sestamibi is administered intravenously ap- carefully considered before embarking on proximately 2hrs prior to surgery; this time expensive investigations and repeat sur- delay allows for a high concentration of gery: isotope to be retained within the para- • Is the diagnosis of primary hyperparathyroid adenoma whilst it has started to thyroidism correct, or is there an alter- wash out from other sites of uptake such native explanation for the endocrine the salivary glands and thyroid. A gamma abnormalities? camera is used intra-operatively to identify • Differentiate recurrent parathyroid the adenoma. disease from persistent hyperparathyroidism: did PTH levels drop following Minimally invasive parathyroid surgery: the 1st operation, or did they remain Several techniques have been devised to elevated? reduce the length of the skin incision and to bring the putative benefits of minimally • Obtain surgical notes of the primary invasive techniques to thyroid and para- procedure, histology reports, and post- thyroid surgery. Minimally invasive para- operative endocrinology records thyroidectomy can be performed via a

limited 2-3cm cervical incision with visual If a convincing case can be made for re- assistance of an endoscope, but since it can exploration, then the most helpful imaging be performed with a similarly sized inci- remains Tc99m-sestamibi and cervical US. sion with direct visualisation, this techni- If both are negative, then a CT-scan may que is not widely used. add useful information. Whilst potential ectopic locations of parathyroids should be

13 Useful References THE OPEN ACCESS ATLAS OF OTOLARYNGOLOGY, HEAD & 1. Mohebati A, Shaha AR. Anatomy of Thyroid and Parathyroid Glands and NECK OPERATIVE SURGERY www.entdev.uct.ac.za Neurovascular Relations. Clin Anat. 2012;25(1):19-31 2. Wang C. The anatomic basis of para-

thyroid surgery. Ann Surg. 1976; 183: 271–5 The Open Access Atlas of Otolaryngology, Head & Neck Operative Surgery by Johan Fagan (Editor) 3. Fraser WD. Hyperparathyroidism. The [email protected] is licensed under a Creative Lancet. 2009;374:145–58 Commons Attribution - Non-Commercial 3.0 Unported 4. Adler JT, Sippel RS, Chen H. New License Trends in Parathyroid Surgery. Curr Probl Surg. 2010;47(12):958-1017 5. Lew JI, Solorzano CC. Surgical Mana- gement of Primary Hyperparathyroi- dism: State of the Art. Surg Clin N Am. 2009;89:1205–25 6. Pitt SC, Sippel RS, Chen H. Secondary and Tertiary Hyperparathyroidism: State of the Art Surgical Management. Surg Clin N Am. 2009;89:1227–39

Thyroidectomy under local and regional (cervical plexus block) anaesthesia https://vula.uct.ac.za/access/content/group/ ba5fb1bd-be95-48e5-81be- 586fbaeba29d/Thyroidectomy%20under% 20local%20and%20regional%20anaesthesi a.pdf

Author

Eugenio Panieri MBChB, FCS Associate Professor Division of General Surgery University of Cape Town Cape Town, South Africa [email protected]

2nd Author and Editor

Johan Fagan MBChB, FCS(ORL), MMed Professor and Chairman Division of Otolaryngology University of Cape Town Cape Town, South Africa [email protected]